Subject: Re: [AUDITORY] Footsteps in the womb From: "Prof. Efthymios Papatzikis" <efp331@xxxxxxxx> Date: Sat, 6 Dec 2025 08:27:19 +0400--Apple-Mail=_A621B4AB-65F7-4240-B8EC-7E08A7942F0F Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 Hi Rob, As you correctly point, in gestation the external canal and middle ear = are not air-filled in the way we usually assume for postnatal hearing, = so the classic air-conduction middle-ear transformer is not really = operating in its standard form. That=E2=80=99s exactly why it is a bit = misleading to talk as if the fetus =E2=80=9Chears=E2=80=9D in the same = mechanical sense as a term newborn or adult. In practice, I would say that when we try to estimate fetal = =E2=80=9Chearing=E2=80=9D in this context, I understand from the = relevant literature that we usually don=E2=80=99t build an explicit = =E2=80=9Cfluid-on-both-sides=E2=80=9D middle-ear model. Instead we = either measure the intrauterine vibroacoustic field directly with = hydrophones near the fetus (e.g., Benzaquen et al., 1990; Richards et = al., 1992), or model transmission from the external environment into the = uterus using anatomical/finite-element models (e.g., G=C3=A9lat et al., = 2025). A review by Gerhardt and Abrams (2000) summarizes quite well how = these measurements translate into fetal exposures. Therefore, in my understanding, functional cochlear activation should be = treated as being driven mainly by bone- and tissue-conducted, strongly = low-pass filtered vibroacoustic energy (dispersed in the whole of the = fetus body), with the unusual mechanics of the fetal ear (including the = fluid filling) effectively folded into those empirical transfer = functions and into the elevated behavioral/physiological thresholds = relative to postnatal air-conducted hearing. So when we talk about = =E2=80=9Chearing in the womb,=E2=80=9D it is really shorthand for = auditory pathway activation under these nonstandard mechanical = conditions, rather than the usual air-conduction case. I hope I somewhat answered your answer. All the best, Efthymios Refs: Benzaquen, S., Gagnon, R., Hunse, C., & Foreman, J. (1990). The = intrauterine sound environment of the human fetus during labor. American = Journal of Obstetrics and Gynecology, 163(2), 484=E2=80=93490. Richards, D. S., Frentzen, B., Gerhardt, K. J., McCann, M. E., & Abrams, = R. M. (1992). Sound levels in the human uterus. Obstetrics & Gynecology, = 80(2), 186=E2=80=93190. G=C3=A9lat, P., Van=E2=80=99t Wout, E., Haqshenas, R., Melbourne, A., = David, A. L., Mufti, N., Henriques, J., Thibaut de Maisi=C3=A8res, A., & = Jauniaux, E. (2025). Evaluation of fetal exposure to environmental noise = using a computer-generated model. Nature Communications, 16, 3916. Gerhardt, K. J., & Abrams, R. M. (2000). Fetal exposures to sound and = vibroacoustic stimulation. Journal of Perinatology, 20(8, Suppl. 2), = S21=E2=80=93S30 > On 6 Dec 2025, at 05:12, Maher, Rob <rmaher@xxxxxxxx> wrote: >=20 > Sorry for a completely novice question, but I have been curious about = fetal auditory function: presumably, the ear canal and middle ear are = full of amniotic fluid, so any sound perception would need to be modeled = with fluid on both sides of the eardrum=E2=80=A6 How is this effect = taken into account in estimating =E2=80=9Chearing=E2=80=9D in the womb? > =20 > Curious, > Rob Maher > =20 > =20 > =20 > =20 > From: AUDITORY - Research in Auditory Perception = <AUDITORY@xxxxxxxx <mailto:AUDITORY@xxxxxxxx>> On Behalf = Of Prof. Efthymios Papatzikis > Sent: Thursday, December 4, 2025 11:01 PM > To: AUDITORY@xxxxxxxx <mailto:AUDITORY@xxxxxxxx> > Subject: Re: Footsteps in the womb > =20 > **External Sender** >=20 > Dear Jonathan, >=20 > Thanks for sending this around =E2=80=93 it is a really stimulating = idea. >=20 > Personally speaking, I am not aware of any empirical work that has = actually measured maternal footsteps - or any other rhythmic movement = induced sound - in utero. The studies I know of on the intrauterine = soundscape (I am not a specialist in this field as I work mostly with = premature infants- so do not take my word for it) give global levels and = spectra, but not event-specific waveforms, so I do not think we = currently have data that would let you specify a =E2=80=9Creal=E2=80=9D = amplitude envelope for footsteps in a strong, evidence-based way. >=20 > Conceptually, I would be inclined to treat gait-related input as slow, = low-frequency modulations of an already noisy vibroacoustic field, = tightly coupled to vestibular input, rather than as discrete, sharply = defined acoustic impulses. In any given case SNR for any = =E2=80=98=E2=80=9Cauditory=E2=80=9D related source (even if assumed; = considering also that the intrauterine acoustic neurosystemic function = is not the same as ex-utero) will be too low considering the already = messy sound environment in utero. =20 >=20 > I think that one way to make this useful in your modeling would be to = show that your results are robust across a family of plausible = envelopes: e.g., band-limited low-frequency =E2=80=9Cbursts=E2=80=9D = with different rise times, durations, and dynamic ranges, all occurring = at gait rate and co-occurring with vestibular cycles. That lets you = argue that what really matters is the regular, low-frequency temporal = structure and multi-sensory coupling, not the precise acoustic fine = structure of each step. >=20 > I=E2=80=99d be very happy to discuss further or look at a = draft/preprint if that would be useful. >=20 > All best, > Efthymios >=20 > Professor Efthymios (Timos) Papatzikis=20 > PhD, PhD, FHEA, Cert.Neuro. > - Neuroscience and Medical Psychology, School of Health Sciences and = Psychology, Canadian University Dubai, U.A.E. > - NICU Senior Research Fellow, =E2=80=98Panagiotis and Aglaia = Kyriakou=E2=80=99 Children=E2=80=99s Hospital, Athens, Greece > - World Health Organization roster of consultants for Brain Health > - World Health Organization certified specialist for Social = Prescribing > - Associate Editor - Frontiers in Pediatric Psychology Journal >=20 > I may write emails at unusual hours. Please don=E2=80=99t feel = obligated to reply until your normal working time. Our personal time and = moments with family are limited and precious; safeguarding them helps us = bring our best to our work. >=20 >=20 > On 5 Dec 2025, at 00:03, Jonathan Cannon <cannoj9@xxxxxxxx = <mailto:cannoj9@xxxxxxxx>> wrote: > =20 > Dear all, > I've done some modeling arguing that the audio/vestibular pairing of = maternal gait inside the womb could scaffold the development of beat = perception and the urge to move to music. To respond to reviewers, I = need to argue that maternal footsteps are indeed audible inside the womb = and give some sense of what the amplitude envelope of the sound would = look like. Does anyone have any thoughts about how to go beyond basic = assumptions (I've been assuming audible, low-pass-filtered impulses) to = get a better sense of what maternal footsteps sound like inside the = womb? > (Reply to me directly -- doesn't seem worth starting a long chain = about this) > Thanks, > Jonathan --Apple-Mail=_A621B4AB-65F7-4240-B8EC-7E08A7942F0F Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 <html aria-label=3D"message body"><head><meta http-equiv=3D"content-type" = content=3D"text/html; charset=3Dutf-8"></head><body = style=3D"overflow-wrap: break-word; -webkit-nbsp-mode: space; = line-break: after-white-space;"><p data-start=3D"156" data-end=3D"163" = style=3D"caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0);">Hi Rob,</p><p = data-start=3D"165" data-end=3D"543" style=3D"caret-color: rgb(0, 0, 0); = color: rgb(0, 0, 0);">As you correctly point, in gestation the external = canal and middle ear are not air-filled in the way we usually assume for = postnatal hearing, so the classic air-conduction middle-ear transformer = is not really operating in its standard form. That=E2=80=99s exactly why = it is a bit misleading to talk as if the fetus =E2=80=9Chears=E2=80=9D = in the same mechanical sense as a term newborn or adult.</p><p = data-start=3D"545" data-end=3D"1097" style=3D"caret-color: rgb(0, 0, 0); = color: rgb(0, 0, 0);">In practice, I would say that when we try to = estimate fetal =E2=80=9Chearing=E2=80=9D in this context, I understand = from the relevant literature that we usually don=E2=80=99t build an = explicit =E2=80=9Cfluid-on-both-sides=E2=80=9D middle-ear model. Instead = we either measure the intrauterine vibroacoustic field directly with = hydrophones near the fetus (e.g., Benzaquen et al., 1990; Richards et = al., 1992), or model transmission from the external environment into the = uterus using anatomical/finite-element models (e.g., G=C3=A9lat et al., = 2025). A review by Gerhardt and Abrams (2000) summarizes quite well how = these measurements translate into fetal exposures.</p><p = data-start=3D"1099" data-end=3D"1708" style=3D"caret-color: rgb(0, 0, = 0); color: rgb(0, 0, 0);">Therefore, in my understanding, functional = cochlear activation should be treated as being driven mainly = by <span data-start=3D"1180" data-end=3D"1259">bone- and = tissue-conducted, strongly low-pass filtered vibroacoustic energy = (dispersed in the whole of the fetus body)</span>, with the unusual = mechanics of the fetal ear (including the fluid filling) effectively = folded into those empirical transfer functions and into the elevated = behavioral/physiological thresholds relative to postnatal air-conducted = hearing. So when we talk about =E2=80=9Chearing in the womb,=E2=80=9D it = is really shorthand for auditory pathway activation under these = nonstandard mechanical conditions, rather than the usual air-conduction = case.</p><p data-start=3D"1099" data-end=3D"1708" style=3D"caret-color: = rgb(0, 0, 0); color: rgb(0, 0, 0);">I hope I somewhat answered your = answer.</p><p data-start=3D"1710" data-end=3D"1731" style=3D"caret-color: = rgb(0, 0, 0); color: rgb(0, 0, 0);">All the best,<br data-start=3D"1719" = data-end=3D"1722">Efthymios</p><p data-start=3D"1710" data-end=3D"1731" = style=3D"caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0);">Refs:</p><p = data-pm-slice=3D"1 1 []" style=3D"caret-color: rgb(0, 0, 0); color: = rgb(0, 0, 0);">Benzaquen, S., Gagnon, R., Hunse, C., & Foreman, J. = (1990). The intrauterine sound environment of the human fetus during = labor. American Journal of Obstetrics and Gynecology, 163(2), = 484=E2=80=93490.</p><p style=3D"caret-color: rgb(0, 0, 0); color: rgb(0, = 0, 0);">Richards, D. S., Frentzen, B., Gerhardt, K. J., McCann, M. E., = & Abrams, R. M. (1992). Sound levels in the human uterus. Obstetrics = & Gynecology, 80(2), 186=E2=80=93190.</p><p style=3D"caret-color: = rgb(0, 0, 0); color: rgb(0, 0, 0);">G=C3=A9lat, P., Van=E2=80=99t Wout, = E., Haqshenas, R., Melbourne, A., David, A. L., Mufti, N., Henriques, = J., Thibaut de Maisi=C3=A8res, A., & Jauniaux, E. (2025). Evaluation = of fetal exposure to environmental noise using a computer-generated = model. Nature Communications, 16, 3916.</p><p style=3D"caret-color: = rgb(0, 0, 0); color: rgb(0, 0, 0);">Gerhardt, K. J., & Abrams, R. M. = (2000). Fetal exposures to sound and vibroacoustic stimulation. Journal = of Perinatology, 20(8, Suppl. 2), S21=E2=80=93S30</p><div><br><blockquote = type=3D"cite"><div>On 6 Dec 2025, at 05:12, Maher, Rob = <rmaher@xxxxxxxx> wrote:</div><br = class=3D"Apple-interchange-newline"><div><meta charset=3D"UTF-8"><div = class=3D"WordSection1" style=3D"page: WordSection1; caret-color: rgb(0, = 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; = font-variant-caps: normal; font-weight: 400; letter-spacing: normal; = text-align: start; text-indent: 0px; text-transform: none; white-space: = normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; = text-decoration: none;"><div style=3D"margin: 0in; font-size: 12pt; = font-family: Aptos, sans-serif;">Sorry for a completely novice question, = but I have been curious about fetal auditory function: presumably, = the ear canal<span = class=3D"Apple-converted-space"> </span><i>and</i><span = class=3D"Apple-converted-space"> </span>middle ear are full of = amniotic fluid, so any sound perception would need to be modeled with = fluid on both sides of the eardrum=E2=80=A6 How is this effect taken = into account in estimating =E2=80=9Chearing=E2=80=9D in the = womb?<o:p></o:p></div><div style=3D"margin: 0in; font-size: 12pt; = font-family: Aptos, sans-serif;"><o:p> </o:p></div><div = style=3D"margin: 0in; font-size: 12pt; font-family: Aptos, = sans-serif;">Curious,<o:p></o:p></div><div style=3D"margin: 0in; = font-size: 12pt; font-family: Aptos, sans-serif;">Rob = Maher<o:p></o:p></div><div style=3D"margin: 0in; font-size: 12pt; = font-family: Aptos, sans-serif;"><o:p> </o:p></div><div = style=3D"margin: 0in; font-size: 12pt; font-family: Aptos, = sans-serif;"><o:p> </o:p></div><div style=3D"margin: 0in; = font-size: 12pt; font-family: Aptos, = sans-serif;"><o:p> </o:p></div><div style=3D"margin: 0in; = font-size: 12pt; font-family: Aptos, = sans-serif;"><o:p> </o:p></div><div><div style=3D"border-width: 1pt = medium medium; border-style: solid none none; border-color: rgb(225, = 225, 225) currentcolor currentcolor; border-image: none; padding: 3pt = 0in 0in;"><div style=3D"margin: 0in; font-size: 12pt; font-family: = Aptos, sans-serif;"><b><span style=3D"font-size: 11pt; font-family: = Calibri, sans-serif;">From:</span></b><span style=3D"font-size: 11pt; = font-family: Calibri, sans-serif;"><span = class=3D"Apple-converted-space"> </span>AUDITORY - Research in = Auditory Perception <<a href=3D"mailto:AUDITORY@xxxxxxxx" = style=3D"color: rgb(70, 120, 134); text-decoration: = underline;">AUDITORY@xxxxxxxx</a>><span = class=3D"Apple-converted-space"> </span><b>On Behalf Of<span = class=3D"Apple-converted-space"> </span></b>Prof. Efthymios = Papatzikis<br><b>Sent:</b><span = class=3D"Apple-converted-space"> </span>Thursday, December 4, 2025 = 11:01 PM<br><b>To:</b><span = class=3D"Apple-converted-space"> </span><a = href=3D"mailto:AUDITORY@xxxxxxxx" style=3D"color: rgb(70, 120, = 134); text-decoration: = underline;">AUDITORY@xxxxxxxx</a><br><b>Subject:</b><span = class=3D"Apple-converted-space"> </span>Re: Footsteps in the = womb<o:p></o:p></span></div></div></div><div style=3D"margin: 0in; = font-size: 12pt; font-family: Aptos, = sans-serif;"><o:p> </o:p></div><p style=3D"line-height: 12pt; = background: rgb(255, 204, 102);"><strong><span style=3D"font-family: = Aptos, sans-serif;">**External Sender**</span></strong><span = style=3D""></span><o:p></o:p></p><div><p style=3D"caret-color: rgb(0, 0, = 0);"><span style=3D"">Dear Jonathan,<o:p></o:p></span></p><p = style=3D"caret-color: rgb(0, 0, 0);"><span style=3D"">Thanks for sending = this around =E2=80=93 it is a really stimulating = idea.<o:p></o:p></span></p><p style=3D"caret-color: rgb(0, 0, 0);"><span = style=3D"">Personally speaking, I am not aware of any empirical work = that has actually measured maternal footsteps - or any other rhythmic = movement induced sound - in utero. The studies I know of on the = intrauterine soundscape (I am not a specialist in this field as I work = mostly with premature infants- so do not take my word for it) give = global levels and spectra, but not event-specific waveforms, so I do not = think we currently have data that would let you specify a =E2=80=9Creal=E2= =80=9D amplitude envelope for footsteps in a strong, evidence-based = way.<o:p></o:p></span></p><p style=3D"caret-color: rgb(0, 0, 0);"><span = style=3D"">Conceptually, I would be inclined to treat gait-related input = as slow, low-frequency modulations of an already noisy = vibroacoustic field<strong><span style=3D"font-family: Aptos, = sans-serif;">,<span = class=3D"Apple-converted-space"> </span></span></strong>tightly = coupled to vestibular input, rather than as discrete, sharply defined = acoustic impulses. In any given case SNR for any =E2=80=98=E2=80=9Cauditor= y=E2=80=9D related source (even if assumed; considering also that the = intrauterine acoustic neurosystemic function is not the same as = ex-utero) will be too low considering the already messy sound = environment in utero. <o:p></o:p></span></p><p style=3D"caret-color:= rgb(0, 0, 0);"><span style=3D"">I think that one way to make this = useful in your modeling would be to show that your results are robust = across a family of plausible envelopes: e.g., band-limited = low-frequency =E2=80=9Cbursts=E2=80=9D with different rise times, = durations, and dynamic ranges, all occurring at gait rate and = co-occurring with vestibular cycles. That lets you argue that what = really matters is the <strong><span style=3D"font-family: Aptos, = sans-serif;">r</span></strong>egular, low-frequency temporal structure = and multi-sensory coupling, not the precise acoustic fine structure of = each step.<o:p></o:p></span></p><p style=3D"caret-color: rgb(0, 0, = 0);"><span style=3D"">I=E2=80=99d be very happy to discuss further or = look at a draft/preprint if that would be = useful.<o:p></o:p></span></p><p style=3D"caret-color: rgb(0, 0, = 0);"><span style=3D"">All = best,<br>Efthymios<o:p></o:p></span></p><div><div><div><div = style=3D"margin: 0in; font-size: 12pt; font-family: Aptos, = sans-serif;"><b><span style=3D"">Professor = Efthymios (Timos) Papatzikis</span></b> <br><i><span = style=3D"">PhD, PhD, FHEA, Cert.Neuro.</span></i><br><span = style=3D"font-size: 8.5pt;">- Neuroscience and Medical = Psychology, School of Health Sciences and Psychology, Canadian = University Dubai, U.A.E.<br>- NICU Senior Research = Fellow, =E2=80=98Panagiotis and Aglaia Kyriakou=E2=80=99 = Children=E2=80=99s Hospital, Athens, Greece<br>- World Health = Organization roster of consultants for Brain Health<br>- World = Health Organization certified specialist for = Social Prescribing<br>- Associate Editor - Frontiers = in Pediatric Psychology Journal</span><br><br><i><span = style=3D"font-size: 8.5pt; font-family: Helvetica-LightOblique, serif; = color: rgb(255, 55, 17);">I may write emails at unusual hours. = Please don=E2=80=99t feel obligated to reply until your = normal working time. Our personal time and moments with family = are limited and precious; safeguarding them helps us bring our best = to our work.</span></i><o:p></o:p></div></div></div></div><div><div = style=3D"margin: 0in; font-size: 12pt; font-family: Aptos, = sans-serif;"><br><br><o:p></o:p></div><blockquote style=3D"margin-top: = 5pt; margin-bottom: 5pt;"><div><div style=3D"margin: 0in; font-size: = 12pt; font-family: Aptos, sans-serif;">On 5 Dec 2025, at 00:03, Jonathan = Cannon <<a href=3D"mailto:cannoj9@xxxxxxxx" style=3D"color: = rgb(70, 120, 134); text-decoration: = underline;">cannoj9@xxxxxxxx</a>> = wrote:<o:p></o:p></div></div><div style=3D"margin: 0in; font-size: 12pt; = font-family: Aptos, sans-serif;"><o:p> </o:p></div><div><div><div = style=3D"margin: 0in; font-size: 12pt; font-family: Aptos, = sans-serif;">Dear all,<o:p></o:p></div></div><div style=3D"margin: 0in; = font-size: 12pt; font-family: Aptos, sans-serif;">I've done some = modeling arguing that the audio/vestibular pairing of maternal gait = inside the womb could scaffold the development of beat perception and = the urge to move to music. To respond to reviewers, I need to argue = that maternal footsteps are indeed audible inside the womb and give some = sense of what the amplitude envelope of the sound would look like. Does = anyone have any thoughts about how to go beyond basic assumptions (I've = been assuming audible, low-pass-filtered impulses) to get a better sense = of what maternal footsteps sound like inside the = womb?<o:p></o:p></div><div style=3D"margin: 0in; font-size: 12pt; = font-family: Aptos, sans-serif;">(Reply to me directly -- doesn't seem = worth starting a long chain about this)<o:p></o:p></div><div = style=3D"margin: 0in; font-size: 12pt; font-family: Aptos, = sans-serif;">Thanks,<o:p></o:p></div><div style=3D"margin: 0in; = font-size: 12pt; font-family: Aptos, = sans-serif;">Jonathan</div></div></blockquote></div></div></div></div></bl= ockquote></div><br></body></html>= --Apple-Mail=_A621B4AB-65F7-4240-B8EC-7E08A7942F0F--